/*
 * Copyright 2017 Huawei Technologies Co., Ltd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.servicecomb.foundation.common;

import java.util.Collection;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class RegisterManager<KEY, VALUE> {
    private static final Logger LOGGER = LoggerFactory.getLogger(RegisterManager.class);

    private String name;

    private String registerErrorFmt = "Not allow regsiter repeat data, name=%s, key=%s";

    private Map<KEY, VALUE> objMap = new ConcurrentHashMap<>();

    private Object lockObj = new Object();

    public RegisterManager(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public String getRegisterErrorFmt() {
        return registerErrorFmt;
    }

    public void setRegisterErrorFmt(String registerErrorFmt) {
        this.registerErrorFmt = registerErrorFmt;
    }

    public void register(KEY key, VALUE value) {
        synchronized (lockObj) {
            if (objMap.get(key) != null) {
                // 不允许重复注册
                String msg = String.format(registerErrorFmt, name, key);
                LOGGER.error(msg);

                // 禁止启动
                throw new Error(msg);
            }
            objMap.put(key, value);
        }
    }

    public VALUE findValue(KEY key) {
        return objMap.get(key);
    }

    public VALUE ensureFindValue(KEY key) {
        VALUE value = objMap.get(key);
        if (value == null) {
            String msg = String.format("Can not find value, name=%s, key=%s", name, key);
            throw new Error(msg);
        }

        return value;
    }

    public Collection<KEY> keys() {
        return objMap.keySet();
    }

    public Collection<VALUE> values() {
        return objMap.values();
    }
}
